A polytunnel structure is described which comprises a plurality of rows (10) of leg members (12), and a plurality of cover support members (20), each cover support member (20) being supported at one end by a leg (12) of one of the rows (10), and at its opposite end by a corresponding leg (12) of an adjacent one of the rows (10), wherein at least one of the cover support members (20) is of tubular form of non-circular cross-sectional shape having a major axis (22) and a minor axis (24), wherein, in use, the minor axis (24) extends generally parallel to a ground surface upon which the polytunnel structure is used, and the major axis (22) extends perpendicularly to the minor axis (24).
